No Range Rover Classics were built after 1995 - the late 90s and early 2000s RR is the P38. That is a very comfortable and capable car, but it is notorious for EAS and BECM faults (both expensive) and for porous blocks on the 4.2l V8 engine. On the flip-side, they are available quite cheaply because many people won't touch them because of these maintenance concerns. A coil spring conversion from someone like Atlantic British would prevent any EAS issues, and the BECMs, though not available new anymore, would be available at a price from a scrap yard - it's usually dry joints that let the BECM down, so they're usually repairable if you are very patient or have a good electronics specialist at hand.
The Range Rover Classic has a similar EAS system in its dusk years (it was essentially a test mule for the P38) which is very unreliable unless recently overhauled. Other than that and its notorious rust issues in the inner body shell, it's a fairly easy car to keep going, but due to the vehicles' age, it's likely to have a list of niggling faults. There isn't much space for drivers over 6' and rear passenger have very little space unless you find an LSE (LWB).
The Discovery I was based on the RRC, and whule it lacks the style or prestige of the RRC, it does gain a lot of extra space for the second row and the boot. It has the same problems as the RRC.
The Discovery II looks similar to the DI, but is quite different under the skin. It has the same transmission options, but that's pretty much it. They're well built and much more resistant to rust. their biggest problem was the lack of a centre diff lock, relying entirely on ETC on the early vehicles. Five seaters have coil sprung suspension while seven seaters have rear EAS and front ACE, which are expensive to repair and are an un-necessary complication - a coil conversion would be a good idea.